CN104412118A - Methods and systems for improved magnetic resonance acquisition - Google Patents

Abstract

Magnetic resonance imaging methods and apparatus for simultaneous measurement of the physical properties R1 and R2 relaxation rate, proton density, and apparent diffusion coefficient using a single magnetic resonance acquisition.

Description

The method and system of the magnetic resonance acquisition improved

Technical field

The present invention relates to for improvement of the method for magnetic resonance acquisition, system and computer program.Particularly, the present invention relates to for using integral type (single) magnetic resonance acquisition to measure physical attribute R simultaneously ₁and R ₂the method of relaxation rate, proton density and apparent diffusion coefficient, system and computer program.

Background technology

Magnetic resonance imaging (MRI) can produce the cross sectional image in any plane (comprising inclined-plane).Medical treatment MRI major part often depends on the relaxation attribute of the hydrogen nuclei (proton) excited in water and fat.When the object of imaging is placed in strong uniform magnetic field, there is in tissue the nuclear spin of non-integer spin population or be parallel to magnetic field or antiparallel and align.The Output rusults of MRI scanning is MRI contrast images or a series of MRI contrast images.

In order to understand MRI contrast, it is very important for having some understandings to time constant involved in the relaxation process of equilibrium establishment after RF excites.Because the proton relaxation be excited and rearranging, they carry out radiant with the speed being recorded the information providing the environment about them.Rearranging of the proton spin in magnetic field is utilized to be called as longitudinal relaxation, and speed (the about 1s usually required for the alignment of the tissue core of certain percentage ^-1) be called as " R ₁relaxation rate " or R ₁.Fall apart phase in the local that the imaging of T2 weighting depends on the spin of the application of following transverse energy pulse; Transverse relaxation rate is (for organizing usual >10s ^-1) be called as " R ₂relaxation rate " or R ₂.These relaxation rates are also expressed as relaxation time T ₁(=1/R ₁) and T ₂(=1/R ₂).Total signal relies on quantity or the proton density PD of proton.Because the random motion (process that can be strengthened by the application of large bipolar gradient) of proton decreases total signal; Motion proton obtains the phase differential causing the other loss of signal.The loss of signal indicates the diffusion of hydrone and can be measured as apparent diffusion coefficient ADC.The measurement result that the direction of spreading occurs wherein is called as Fractional anisotropy FA.At scanner control desk, all available parameters, such as the application of echo time TE, repetition time TR, flip angle α and priming pulse and gradient (and more), is set to particular value.The parameter of each particular group creates the signal specific intensity in the image as a result of the feature depending on measured tissue.

Usual MR image is qualitatively in itself: absolute image signal intensity, without any meaning, is difference in signal strength, contrast by what explain.This causes the subjectivity of image to be understood, intrinsic inaccuracy and user's dependence.On the other hand, the target that MR quantizes is the measurement result of the physical attribute in absolute scale.This provide the stable basis of target measurement and automatic tissue identification.Example is the measurement of the pathology load to the cranial capacity of dementia subsequently, the dose,tumor of oncology and multiple sclerosis.

There is the lasting demand to the improvement of MR imaging.Thus be provided for obtaining physical attribute such as R ₁, R ₂, PD and ADC measurement improvement and faster method make us thirst for.

Summary of the invention

The object of this invention is to provide the method and apparatus overcoming the above-mentioned at least part of problem pointed out.

This object and other potential objects are obtained by the method and apparatus of stating in the following claims.

According to embodiment described herein, a kind of integral type magnetic resonance acquisition that uses is provided to estimate R ₁and R ₂the method of relaxation time, proton density PD.According to some embodiments, use the integral type magnetic resonance acquisition provided can also estimate apparent diffusion coefficient ADC.According to depending on some embodiments how carrying out arranging, R can be estimated simultaneously ₁-R ₂-PD or R ₁-R ₂-PD-ADC.

In mri, exist influential three the main physical attributes of the signal intensity in MR image: longitudinal R ₁relaxation rate (T ₁the inverse in relaxation time), horizontal R ₂relaxation rate (T ₂the inverse in relaxation time) and proton density PD.Utilize quantitative MRI can measure this three attributes.Compared with causing traditional MR imaging of the qualitative picture with relative image intensity scale, quantitative MRI scanning can cause measuring physical attribute such as R with absolute scale ₁, R ₂and PD.These values arrange independent of scanner and therefore directly react tissue below.Thus, each organization type has the R of himself ₁, R ₂with the Feature Combination of PD.Such as, the mean value of the white matter in brain is approximately (R ₁, R ₂, PD) and=(1.7s ^-1, 14s ^-1, 64%), be (1.0s for grey matter ^-1, 12s ^-1, 85%), be (0.24s for brains liquid ^-1, 1.5s ^-1, 100%) and (see " the Rapid MagneticResonance Quantification on the Brain:Optimization for Clinical UsageMagnResonMed 2008 of the people such as such as Warntjes; 60:320-329).The common value of ADC is 0.9,0.8 and 4.010 respectively ^-3mm/s.Comprising the multiparameter R of noise measurement and partial volume effects ₁-R ₂region in-PD-ADC space can be designated as and comprise brain tissue and CSF.These values are different from such as muscle or fat.

According to some embodiments, MR attribute corresponds to R ₁and R ₂relaxation rate or proton density or at least one in the relaxation time, wherein T ₁=1/R ₁and T ₂=1/R ₂.

According to embodiment described herein, provide the method using integral type gradient echo acquisition mode simultaneously to estimate the magnetic resonance imaging of multiple physical parameter.The method comprises the gradient echo acquisition of the parallel segmentation of acquisition at least three.By described collection and R ₁sensitization stage, R ₂sensitization stage and time delay interlock; And gather generation to R according to described at least three ₁and R ₂the measurement of relaxation rate and proton density PD.

According to some embodiments, described at least three collections are performed twice, produce at least six collections, wherein by described collection and at least two R ₁sensitization stage, R ₂sensitization stage, diffusion sensitizing stage and time delay are staggered; And wherein gather according to described at least six and produce R ₁and R ₂the measurement of relaxation rate, proton density PD and apparent diffusion coefficient ADC.

Described collection can be disturb phase gradient collection, also referred to as Turbo Field Echo TFE.In interchangeable embodiment, described collection can be that balance and stability state free precession gathers (bSSFP), also referred to as balance Turbo Field Echo (bTEE).In another embodiment, described collection is echo-planar imaging collection (EPI).This acquisition mode can also be the combination that TFE and EPI gathers.

In addition, described collection can be performed in two-dimentional 2D section.In another embodiment, three-dimensional 3D volume performs described collection.

According to some embodiments, R ₁the sensitization stage comprises 90 degree of RF saturation pulse.According to another embodiment, described R ₁the sensitization stage comprises 180 degree of RF reverse impulses.According to some embodiments, R ₂the sensitization stage comprises 90 degree of RF pulses, 180 degree of refocusing pulses and-90 degree RF pulses.According to some embodiments, described R ₂the sensitization stage comprises 90 degree of RF pulses, multiple 180 degree of refocusing pulses and-90 degree RF pulses.

According to some embodiments, the diffusion sensitizing stage comprises 90 degree of RF pulses, 180 degree of refocusing pulses and-90 degree RF pulses, and wherein said 180 degree of refocusing pulses are crossed over (straddle) by gradient.

According to some embodiments, be used in described R ₁the image intensity signal of all collections after the sensitization stage estimates described R ₁relaxation rate.

According to some embodiments, be used in described R ₂the image intensity signal of the collection before and after the sensitization stage estimates described R ₂relaxation rate.

According to some embodiments, be used in described R ₁the image intensity signal of the collection before and after the sensitization stage estimates the B of the scanner for obtaining described collection ₁.

According to some embodiments, be used in before and after the described diffusion sensitizing stage and at described R ₂the image intensity signal of the collection before and after the sensitization stage estimates ADC.

The present invention also extends to computerized imaging system, it is arranged to perform method described herein and have the digital storage media storing computer program instructions/software segments thereon, impels computing machine to perform method described herein when this computer program instructions/software segments is performed.

One of them of the advantage of method described herein is the physical attribute utilizing integral type sequence can measure patient with absolute scale within the very short time.

Accompanying drawing explanation

In further detail the present invention will be described by non-limitative example and with reference to accompanying drawing below, wherein:

Fig. 1 is the schematic diagram of MR system,

Fig. 2 has R ₁sensitization stage, R ₂the schematic diagram of the MR sequence that sensitization stage and integral type gather, wherein parallel acquisition 5 imaging volumes.

Fig. 3 is two different R ₂sensitization stage (a and b) and the schematic diagram of diffusion sensitizing stage (c).

Fig. 4 a and 4b illustrates to estimate such as R ₁, R ₂, PD and ADC physical attribute time the process flow diagram of some steps that performs.

Embodiment

In the following description, for explanation and unrestriced object, sets forth specific details is certain architectures, interface, technology etc. such as.But, it will be obvious to those skilled in the art that the technology that can realize with other embodiments not deviating from these details describing.That is, although do not describe clearly herein or illustrate, those skilled in the art can the various layouts of principle of technology described by design indicates.In some instances, eliminate the detailed description of known equipment, circuit and method, not make the fuzzy description of the invention of unnecessary details.The equivalent that all statements of principle, aspect and embodiment and its concrete example are all intended to comprise its 26S Proteasome Structure and Function is described herein.In addition, it is intended to the equivalent that such equivalent comprises current known equivalent and following exploitation, is namely developed any element performing identical function, and does not consider structure.

Thus, such as, it will be appreciated by those skilled in the art that block diagram herein represents the conceptual view of the illustrative circuitry of the principle embodying this technology.Similarly, should be appreciated that the various process of description can be showed with the form of computer-readable medium substantially and can be performed by computing machine or processor.

By using specialized hardware and the hardware of executive software can providing the function of the various elements comprising function declaration.When using computer processor, can by single application specific processor, provide these functions by single share processor or by multiple independent processor (some of them are shared or distributed).Further, controller described herein can comprise but not limit number word signal processor (DSP) hardware, ASIC hardware, ROM (read-only memory) (ROM), random access memory (RAM) and/or other reservoir media.

In FIG, the general view of the foundation of MRI system 100 is described.System 100 comprises MR scanner 101.MR scanner operationally produces MRI data by the mode scanning lived object.MR scanner also connects the computing machine 103 for the treatment of the data produced by scanner 101.This computing machine comprises the CPU (central processing unit) that is coupled with storer and the many input and output ports for receiving and export data and information.Computing machine 103 receives input command from one or several input equipments represented by input equipment 105 generally.Input equipment can be one or more in computer mouse, keyboard, trace ball or other input equipment any.Computing machine 103 also connects the screen 107 being used for processed scan-data being visualized as contrast images.Especially, computing machine 103 can comprise the controller unit/imaging circuit being arranged to perform method described herein.

Exist influential three the Main physical attributes of the signal intensity in MR image in mri: longitudinal R ₁relaxation rate (T ₁the inverse in relaxation time), horizontal R ₂relaxation rate (T ₂the inverse in relaxation time) and proton density PD.The 4th physical attribute can be obtained: diffusion by applying large bipolar gradient.Any moving spin will obtain the difference because gradient produces, and it causes the loss of signal.Therefore high diffusivity associates with the high loss of signal.Quantitative MRI can be utilized to measure this four attributes with absolute scale.Each tissue has himself R ₁, R ₂with the Feature Combination of PD.Such as, the mean value of the white matter in brain is approximately (R ₁, R ₂, PD) and=(1.7s ^-1, 14s ^-1, 64%), be (1.0s for grey matter ^-1, 12s ^-1, 85%), be (0.24s for brains liquid ^-1, 1.5s ^-1, 100%) and (see the Rapid Magnetic Resonance Quantification on the Brain:Optimizationfor Clinical UsageMagn Reson Med 2008 of the people such as such as Warntjes; 60:320-329).The representative value of ADC is 0.9,0.8 and 4.010 respectively ^-3mm/s.Comprising the multiparameter R of noise measurement and partial volume effects ₁-R ₂region in-PD-ADC space can be designated to comprise brain tissue and CSF.Such as, these values are for muscle or fat difference.

Use the signal intensity of fraction gradient echo sequence detection MR quantized sequences, wherein multiple image is by parallel acquisition.Collection can be any gtadient echo mode, such as disturb the combination that phase gradient collection (also referred to as Turbo Field Echo TFE), balance and stability state free precession collection (bSSFP, also referred to as balance Turbo Field Echo bTEE), echo-planar imaging collection (EPI) or TFE and EPI gather.For piecewise acquisition, per repetition time TR only performs part collection.By repeating TR until complete collection to obtain and gather completely.Then passing through can parallel collection image to the continuous coverage of the image of the separation of segment.

According to some embodiments, when staggered specific sensitization stage and time delay so that parallel acquisition multiple imaging volume when measuring multiple physical parameter simultaneously.

According to an embodiment, in order to measure R ₁, need R ₁sensitization stage and subsequently two or more than two collections.R ₁the sensitization stage such as can comprise 90 degree of RF saturation pulse to arrange longitudinal Mz magnetization for zero.In interchangeable realization, R ₁the sensitization stage can comprise 180 degree of RF reverse impulses and magnetize to longitudinal Mz that reverses.In order to measure R ₂, need R ₂in the sensitization stage, cross over 2 collections.R ₂the sensitization stage such as can comprise 90 degree of RF pulses, one or more 180 degree of RF refocusing pulses and-90 degree RF pulses to utilize R ₂the longitudinal Mz magnetic field of relaxation sensitization.For ADC, need the diffusion sensitizing stage, cross over two collections.Diffusion sensitizing stage and R ₂the sensitization stage is similar, and wherein 180 degree of refocusing pulses are crossed over by gradient.Especially, refocusing pulse can be crossed over by large gradient, so that the region under gradient (zeroth order) impels (significantly) phase place of spin to change.

Exemplify in Fig. 2 for performing R ₁, R ₂with the exemplary method of the combined measurement of PD.By by their sections of being divided into executed in parallel five collection, wherein each section is run by the example kernel of Fig. 4 a.This kernel is repeated until complete collection to each section.Comprise the first collection Acq1 according to the kernel of the example embodiment of Fig. 2, apply R thereafter ₂sensitization stage P _r2, follow the second collection Acq2 and R ₁sensitization stage P _r1.Finally perform the 3rd collection with time delay.Collection subsequently can repeat with the example of three times (Acq3a, Acq3b and Acq3c).

Assuming that gather magnetization not impact, be so used in R ₁sensitization stage P _r1the signal intensity gathered in the example of Acq3a, Acq3b, Acq3c and Acq1 for afterwards 4 times can obtain R1 and PD, and wherein each gathers the magnetization M of i _ifollowing along with P _r1after t time delay _iincrease and increase:

$R_1=\frac{-t_i}{\ln ((M_0-M_i)/M_0)}$

Proton density PD and M ₀proportional.Owing to there is Two Variables, so must at P _r1after 2 different t time delay _igather at least 2 and gather i (namely at least Acq3a and Acq1).

MR scanner can have uneven B ₁, it can be used in R ₁sensitization stage P _r1afterwards and before the ratio of the signal intensity of (in example A cq3 and Acq2) is measured:

B ₁＝acos(M _post-PR1/M _pre-PR1)

Be used in R ₂sensitization stage P _r2before and after the ratio of signal intensity of (in example A cq1 and Acq2) can R2 be obtained:

$R_2=\frac{\ln (M_{\mathrm{pre}-\mathrm{PR}2}/M_{\mathrm{post}-\mathrm{PR}2})}{{\mathrm{\ΔT}}_E}$

In Fig. 3 a and 3b, show the R with 90 degree of RF pulses, one or more 180 degree of refocusing pulses and-90 degree RF pulses ₂two examples in sensitization stage.Time Δ TE corresponds to the mistiming between two 90 degree of RF pulses.For the R combined ₁, R ₂3 (Acq1, Acq2 and Acq3a) with the minimum number of collection that PD measures.

For R ₁, R ₂, PD and ADC the measurement of combination, need the kernel more grown, as Fig. 4 a adds Fig. 4 b example.Here, the example of Fig. 2 must repeat twice, wherein uses R in one example in which ₂sensitization stage P _r2(as illustrated at Fig. 3 b breviary), and in one example in which, utilize diffusion sensitizing stage P _diffreplace P _r2(as what illustrate in figure 3 c) breviary.The delay rate ACD produced by diffusion can according to following formulae discovery:

$\mathrm{ADC}=\frac{\ln (M_{\mathrm{pre}-\mathrm{Pdiff}}/M_{\mathrm{post}-\mathrm{Pdiff}})}{{\mathrm{\ΔT}}_E}-\frac{\ln (M_{\mathrm{pre}-\mathrm{PR}2}/M_{\mathrm{post}-\mathrm{PR}2})}{{\mathrm{\ΔT}}_E}$

For the R combined ₁, R ₂, PD and ADC measurement, minimum collection number is 6 (Acq1, Acq2, Acq3a, Acq4, Acq5 and Acq6a).If all three directions in space all must detect diffusion, the example in Fig. 2 must repeat 4 times.In this case, a P is applied _r2, and there are three different directions x, y and z application three P of diffusion gradient _diff, and the minimum number therefore gathered is 12.

There is impact if gathered to magnetization, digitizing can calculate the magnetization differentiation in TR, wherein can with time stepping Δ t from previous magnetization M _nproduce each magnetization M _n+1.When not having RF pulse, the magnetization is:

M _n+1＝M ₀-(M ₀-M _n)exp(-R ₁Δt)

When there being the RF acquisition pulse of flip angle α, the magnetization is:

$M_{n+1}=M_0^{*}-(M_0^{*}-M_n)\exp (-R_1^{*}\mathrm{\Δt})$

Wherein, R ₁* be the R1 and M that effectively observe ₀* be the M of effectively observation ₀:

$\frac{R_1}{R_1^{*}}=\frac{M_0^{*}}{M_0}=\frac{1-\exp (-R_1{T}_R)}{1-\cos \left(\mathrm{\α}\right)\exp (-R_1{T}_R)}$

Such as, through but not limited to performing the suitable software program that is loaded on the digital storage mediums of computing machine and impelling computing machine to perform above-mentioned steps, can implement in calculating that composition graphs 2 and Fig. 3 describe in steps.The method can also use suitable hardware implementation, this hardware comprise such as in the form of a lookup table from suitable vision circuit and the controller of different model and memory combination.

In fig .4, process flow diagram illustrates when producing R ₁, R ₂some exemplary steps performed during measurement with PD.First in step 401, perform first to gather.Next, in step 403, R is performed ₂the sensitization stage.Then in step 405, perform second to gather.Next, in step 407, perform R ₁the sensitization stage.Then in step 409, there is the stand-by period.Then, in step 411, perform the 3rd and gather.Then in step 413, there is the stand-by period.Last in step 415, gather based on three and produce R ₁, R ₂with the measurement of PD.

In the example embodiment of Fig. 4 a, but order is very important project is circulation, is thus unessential from which project.From R ₁, R ₂with the data of joining the team of PD, gather and the second collection calculating R from first ₂.Gather and the 3rd collection calculating R from first ₁and PD.In the optional step that Fig. 4 a indicates, in order to R ₁with the more stable calculating of PD, the 3rd collection is repeated one or more times.

R is produced to many segmentations simultaneously ₁, R ₂measure operable sequence with PD, the example of false code be provided below:

From section=1 to hop count

Perform collection 1

Perform R ₂the sensitization stage

Perform collection 2

Perform R ₁the sensitization stage

The latency delays time

Perform collection 3

The latency delays time

If needed, repeated acquisition 3 and time delay

}

In interchangeable embodiment, produced the R of combination by the step some other steps being increased to Fig. 4 a ₁, R ₂, PD and ADC measure.Other such step is shown in fig. 4b.First, the step of Fig. 4 a is performed until and comprise step 413.The step subsequently illustrated in fig. 4b can be performed after step 413.Perform the 4th in step 417 to gather.Next, in step 419, perform the diffusion sensitizing stage.Then, in step 421, perform the 5th and gather.Next, in step 423, perform R ₁the sensitization stage.Then there is the stand-by period in step 425.Then, in step 427, perform the 6th and gather.Then in step 429, there is the stand-by period.Last in step 431, gather based on six and produce R ₁, R ₂, PD and ADC measure.According to some embodiments, gather from first and second and calculate R ₂, gather from the first, the 3rd, the 4th and the 6th and calculate R ₁and PD.In interchangeable embodiment, as indicated in figs 4 a and 4b, in order to R ₁with the more stable calculating of PD, repeated acquisition three and/or six.Can be used first, second, the 4th and the 5th collection to be to calculate ADC.

There is provided below and R is produced to many segmentations simultaneously ₁, R ₂, the operable sequence of PD and ADC the example of false code:

From section=1 to hop count

Perform collection 1

Perform R ₂the sensitization stage

Perform collection 2

Perform R ₁the sensitization stage

The latency delays time

Perform collection 3

The latency delays time

If needed, repeated acquisition 3 and time delay

Perform collection 4

Perform the diffusion sensitizing stage

Perform collection 5

Perform R ₁the sensitization stage

The latency delays time

Perform collection 6

The latency delays time

If needed, repeated acquisition 6 and time delay

}

Use method and apparatus described herein can improve MRI scanning.Especially, within the very short time, utilize integral type sequence can measure the physical attribute of patient with absolute scale.

Claims (21)

1. a method for magnetic resonance imaging, it uses integral type gradient echo acquisition mode to estimate multiple physical parameter simultaneously, and described method comprises:

Obtain the gradient echo acquisition of (401,405,411) at least three parallel segmentations;

By the gradient echo acquisition of described segmentation and R ₁sensitization stage, R ₂sensitization stage and time delay staggered (403,407,409); And

Gather from described at least three and produce (415) to R ₁and R ₂the measurement of relaxation rate and proton density PD.

2. the method for claim 1, wherein said at least three collections are performed twice, produce at least six collections; By described collection and at least two R ₁sensitization stage, R ₂sensitization stage, diffusion sensitizing stage and time delay are staggered; And produce R gathering from described at least six ₁and R ₂the measurement of relaxation rate, PD and apparent diffusion coefficient ADC.

3. method as claimed in claim 1 or 2, phase gradient collection is disturbed in wherein said collection.

4. method as claimed in claim 1 or 2, wherein said collection is that balance and stability state free precession gathers bSSFP.

5. method as claimed in claim 1 or 2, wherein said collection is that echo-planar imaging gathers EPI.

6. the method as described in any one in claim 1-5, wherein performs described collection in two-dimentional 2D section.

7. the method as described in any one in claim 1-5, wherein performs described collection on three-dimensional 3D volume.

8. the method as described in any one in claim 1-7, wherein said R ₁the sensitization stage comprises 90 degree of RF saturation pulse.

9. the method as described in any one in claim 1-7, wherein said R ₁the sensitization stage comprises 180 degree of RF reverse impulses.

10. the method as described in any one in claim 1-9, wherein said R ₂the sensitization stage comprises 90 degree of RF pulses, 180 degree of refocusing pulses and-90 degree RF pulses.

11. methods as described in any one in claim 1-9, wherein said R ₂the sensitization stage comprises 90 degree of RF pulses, multiple 180 degree of refocusing pulses and-90 degree RF pulses.

12. methods as described in any one in claim 2-11, the wherein said diffusion sensitizing stage comprises 90 degree of RF pulses, 180 degree of refocusing pulses and-90 degree RF pulses; And described 180 degree of refocusing pulses are crossed over by gradient.

13. methods as described in any one in claim 1-12, are wherein used in described R ₁the image intensity signal of all collections after the sensitization stage estimates R ₁relaxation rate.

14. methods as described in any one in claim 1-13, are wherein used in described R ₂the image intensity signal of the collection before and after the sensitization stage estimates R ₂relaxation rate.

15. methods as described in any one in claim 1-14, are wherein used in described R ₁the image intensity signal of the collection before and after the sensitization stage estimates the B of the scanner for obtaining described collection ₁.

16. methods as described in any one in claim 2-15, are wherein used in before and after the described diffusion sensitizing stage and at described R ₂the image intensity signal of the collection before and after the sensitization stage estimates described ADC.

17. 1 kinds of MR imaging apparatus (100), it estimates multiple physical parameter for using integral type gradient echo acquisition mode simultaneously, and described equipment is configured to:

Obtain at least three gradient echo acquisition that are parallel, segmentation; And

By the gradient echo acquisition of described segmentation and R ₁sensitization stage, R ₂sensitization stage and time delay interlock.

18. equipment as claimed in claim 17, wherein said equipment is also configured to gather from described at least three produce R ₁and R ₂the measurement of relaxation rate and proton density PD.

19. equipment as described in claim 17 or 18, wherein said equipment is configured at least three collections described in twice execution, thus produces at least six collections; And by described collection and at least two R ₁sensitization stage, R ₂sensitization stage, diffusion sensitizing stage and time delay are staggered.

20. equipment as claimed in claim 19, wherein said equipment is also configured to produce R from described at least six collections ₁and R ₂the measurement of relaxation rate, PD and apparent diffusion coefficient ADC.

21. 1 kinds of non-transitory digital storage mediums, it has the computer program instructions stored thereon, when described computer program instructions is performed by computing machine, impels described computing machine to perform following operation:

Obtain the gradient echo acquisition of at least three parallel segmentations;

By the gradient echo acquisition of described segmentation and R ₁sensitization stage, R ₂sensitization stage and time delay interlock; And

Gather from described at least three and produce R ₁and R ₂the measurement of relaxation rate and proton density PD.